Process for producing carbon tetrachloride



Dec. 22, 1942. J. wxMMr-:R 2,305,821

PROCESS FOR PRODUCING CARBON TETRACHLORIDE Filed OCT.. 1, 1958 INVENTOR 5 ATTORNEYS rnemea Dee 221942v PCESS FOB PBDEUCING CABBQN Y TETBCHLOE Josef Wimmer, Burghausen, Bavaria, vested ln the .Allen Property v Application ,ctober 1, 193B, Serial No. 232,824

r 1n october d, les? invention relates w the production of carbon te .ww and hes lor its object to provide e. new and improved process lor this purnoce. A l

It ie own that at high temperatures there is an brlnm between chlorine, perchlorethylene end cerlnon tetrachloride, which may be expreesed by me equation:

moerlmento have already heen roede th the collect of producing perchlorenrlene by heating cerner. tetrechlode to e. 'hielo eemneretnre. wonnen?. of lhgfe. hemietry lolo; 23, n, old). However) t vrene found that heneclrloretnene was elong wltll helreclllorhemol vin conederelcle quantity, 'which heee ver? dictumin@ tnese experlmente.

The object orf the present invention s to Loren pere cerleen tetrachloride by performing the counterreecton:

The procese heretofore 'need for the production ol' cer'oon tetrachloride has. hed es ite ecurce e cheep cerbon, charcoal. However, since the carbon is niet transformed into carbon olsnlphide and es the precipitated sulphur moet elwoye be returned to the operetlon, the process is dlecontlnuous end complicated. It leeds to an impure carbon tetrachloride, which must etill lee subjected to a process of pnridcetlon to remove traces ol sulphur compounds. The odventiene obtelned from the cheap raw meter-lol le largely loot by these unfavorable circumstances.

JIn contrt to the unsatleiactory previous process :cleared to above, my invention provides e. continuous process which requires no aunlllary substances and only very slight euoervlslo end yields very pine carbon tetrachloride in a single opel-etiennel .According to' my process perchloretllylene vapor and chlorine are simultaneously through a chamber heated to '10W-800 C.V The perchlorethylene is partly split 'upln this operation, and chlorinated to carbon tetraafter The perchlorethylene is again conducted from the still lnto the heating zone, with the .addition of an amount of perchlorethylene equal to that used up n the reaction. Throughout the process,

therefore, e current ol' perchlorethylene vapor continuously circulates through a. heating chem- .loer simultaneously traversed by chlorine, and. through the lower part of a fractoneting col umn, The quantitative amounts of the vchlorine end the nerchlorethylene inthe heating zone may ne maintained wltn "variations in the quantity of eller enlastence. Tile most favorable reaction tempereture lies between 'TMP end 86%" l?, the absence of e catalyst. Above della e. considerable ernennt of nenechlorhenzol forme, wllien netnrelly nos on unfavorable etlect upon the output el' carbon tetrachloride. En our process, hereinin detail, hexeohlorethene mls in only e, emell quantity, and therefore no clogeine occlm. ln point el fact, the hexecl'llorethene 'would llkerriee'orm carbon tetrachloride ln the reaction zone, end would not, therefore, entell e lose; out the ornletion o' henachloretienne should 'be molded for the reason that its chlorination to carbon tetrachloride le en endotllermc reaction and would use up heet required the reaction none. On the other hendthe chlorination ol the nazomer-ethylene to cer-bon tetrachloride occurs enothermlcelly. Tneqnnntlty of heet required ln the production ol carbon tetrachloride ln mail quantities may he'coneidereoly reduced by preheatlng the perchlorethylf? to the center o! rthe velongated. ractionating chloride. The vapors containing a heavy charge l oi' carbon tetrachloride are conducted to the ton oi' a continuously operating lractionating column .provided with a dephlegmator and a heatable son; in which the cmorlne and :ne carbon una;

chlc'uidcA are separated from the pexchlorethvlene immediately after their enti-enceinte the column, before appreciable amounts o! the perchlorethylene can comblnelwlth chlorine to `form hexaclalorctbaner A ene vapor. Y

The accom drawing shows diagr medically one emboent o! the process. Ille perchlorethylene ls vaporlzed ln still b. The perchloret'hvlene vapor le conducted through valve aand velocity meter m into euperheater e and thence into the reaction chamber f. The reaction chr ls heat insulated, and is lined with a carbon electrode by means of which it is heated to 700-8fl-C., chlorine being admitted to the reaction chamber from n. The-vapors now from column c @quipped with a dephlegmator d. The eeparatlon'of the carbon tetrachloride and the chlorine from the rmtranstormed perchlorethylene. which returnsto still b, takes place in this` column. An additional amountot the perchlorethylene vapor from still b is conducted directly into column c'through valve p', to air in eecting the separation in said column. Perchlorethylene is allowed to now into the still b from receptacle o through liquid meter I. in an amolmt correspending to the generated carbon te'traclzllox'ldy pass to the fractionation column g, which effects the separation of the carbon tetrachloride from the chlorine. The carbon tetrachloride which evaporates from the sump of this column is condensed in i and stored in collector k. The chlo` rine leaving column g is driven by pump h. over the velocity meter n into the reaction chamber f. At q fresh chlorine is admitted into the system in the measure of its consumption. v

The apparatus shown in the drawing repre'-` sents only one of the possible embodiments of the g 2,805,821 The vapors emanating from the dephlegmator d` process. Instead of circulating the chlorine as in the process described above, it is also possible to operate only with fresh chlorine, in which case the chlorine gasvcontaining carbon tetrachloride may be subjected to a low temperature separatlng-operation. The traces of carbon tetrachloride lstill found in the chlorine gas can then be collected or used as desired.

The following results, for example, were obtained with the system described above, andv operating without preheating: 160 parts of perchlorethylene were passed per hour 'from still b to the heating chamber f, together with 260 parts of chlorine. The temperature of the heating chamber f was maintained at 725 C.. 123 parts of carbon tetrachloride were obtained per hour. The liquid level in b was kept constant with a continuous supply of perchlorethylene. During the entire operation the boiling point of .the contents of the still did not rise above 119 C., the boiling point of pure perchlorethylene. There was in the still a quantity of hexachlorethane amounting t0 only '1.4% 0f the total cai-bcn tetrachloride obtained. Hexachlorbenzol or other br-products were not formed in any appreciable amount.

' The yield, therefore, was practically quantitative. When the operation was performed at 850 C. un-

der the samev conditions, the formation oi' hexachlorbenzol rose to 2.5% of the carbon tetrachloride, without the output of carbon tetrachloride having been increased. which was not to be expected in view of the exothermal course of the reaction. Carbon-like compounds .appeared in the heating chamber, which were absent when ,the process was performed at the lower temperl atures referred to above. Although no preheating was used, the energy consumption in the heatproducing carbon tetrachloride.

'- acted perchlorethylene and which comprises reacting perchlorethylenel and a considerable excess ot chlorine at a temperature of 700-800 C.. and subjecting the reaction product to fractionation.

3. Process for producing carbon tetrachloride which comprises reacting perchlorethylene and a considerable excess of chlorine at a temperature or 700-800 C., subjecting the reaction product to fractionation to separate the carbon tetrachloride and the unreacted chlorine from the perchlorethylene, and then separating the carbon tetrachloride from the chlorine.

4. Process for producing carbon.tetrachloride which comprises reacting perchlorethylen'e and a.

considerable excess of chlorine at a. temperature of '100-800 C., subjecting the reaction product to fractionation to separate the carbon tetrachloride and the unreacted chlorine from the perchlorethylene, separating the carbon tetrachlorlidefrom the chlorlne'by fractionation, and returning the chlorine to the reaction.

5. Process for producing carbon tetrachloride which comprises reacting'perchlorethylene and a considerable excess of chlorine at a temperature of 700-800 C., subjecting the reaction product to fractionation to separate the carbon tetrachloride and the unreacted chlorine from the perchlorethylene, separating the carbon ltetrachloride from the chlorine, and returning the unrechlprine to the reaction.

6. Process for producing carbon tetrachloride which comprises reacting perchlorethylene and aconsiderable excess of chlorine-at a temperature of 700-k800 C.; subjecting the reaction product toV fractionation to separate the carbon tetrachloride and the unreacted chlorine from the perchlorethylene, separating lthe carbon tetrachloride from the chlorine, returning the unreacted perchlorethylene and chlorine to the reaction, and

continuously recirculating the original reactants.

7. Process for producing carbon tetrachloride which comprises continuously reacting perch1or' ethylene vapor and a considerable excess of chlorine at a temperature of D-800 C., continuously passing the resulting reaction mixture containing carbon tetrachloride to the center of s fractionating column to separate the carbon u tetrachloride and the untransformed chlorine from the perchlorethylene. and continuously recirculating the perchlorethylene vapor and the untransformed chlorine through the heating sone and the fraotionating column while adding thereto quantities of the original reactantsequivalent to those used up in the reaction.

I .rosrzrl 4.

2. Process for producing' carbon tetrachloride 

